There are many situations in which it is highly desirable to be able to determine if a label has been tampered with. For example, if the label is to provide a price or other indicator of characteristics of an object and is applied to the object, it is highly desirable to know if the label is removed from the object. Similar concerns apply to documents, containers which are desirably sealed before use, and in a wide variety of other environments; that is, in such environments, the fact that a label has been tampered with is extremely useful information.
According to the present invention a label, and a method of production thereof, are provided which indicate clearly if the label has been tampered with, and also prevent the re-application (except in a tamper evident mode) of the label once it has been removed.
According to a first aspect of the present invention a security label is provided having the following elements: Label stock having a top face and a bottom face. A release coat provided on the label stock bottom face. A non-opaque tie coat provided on the release coat. A coat of pressure sensitive adhesive provided on the tie coat, the tie coat having substantially greater affinity for the adhesive than the release coat. And indicia provided on the tie coat substantially between the adhesive and the tie coat. The pressure sensitive adhesive preferably is opaque permanent adhesive, and the indicia comprises reverse printed alphanumeric characters such as those indicating a problem situation (e.g., the word "void" or "fraud" or "danger", etc.). The label may be a linerless label, having a release coat on the top face of the label stock, as well as informational indicia, and a release liner may be provided covering the pressure sensitive adhesive. Alternatively, instead of the release liner contacting the permanent pressure sensitive adhesive, there can be further sheet stock (e.g., paper stock) engaging the permanent adhesive at a first face thereof, a second tie coat on a second face of the sheet stock, and repositional adhesive on the tie coat. The repositional adhesive has a greater affinity for surfaces to which it is designed to be applied than the non-opaque tie coat has for the release coat on the back of the label stock. In this construction, the repositional adhesive would also allow the label to be clearly removed from most surfaces but would provide a security feature if the label stock was removed, exposing the security words or design.
According to another aspect of the present invention a security label is provided comprising the following elements: Label stock having a top face and a bottom face. A release coat provided on the label stock bottom face. A non-opaque first tie coat provided on the release coat. A coat of permanent pressure sensitive adhesive provided on the first tie coat, the first tie coat having substantially greater affinity for the adhesive than for the release coat. Indicia associated with the first tie coat. Sheet stock having first and second faces, the first face engaging the permanent adhesive. A second tie coat on the sheet stock second face. And repositional adhesive on the second tie coat.
The invention also contemplates a method of making a label from label stock having top and bottom faces. The method comprises the following steps: (a) Applying a release coat to the label stock bottom face. (b) Applying a non-opaque tie coat to the release coat. (c) Reverse printing security indicia on the tie coat. And (d) coating the reverse printing and tie coat with pressure sensitive adhesive. Step (d) may be practiced utilizing a permanent adhesive, and there may be the further step of covering the adhesive with a release liner. Alternatively, there may be the further steps of: (e) applying the first face of the sheet stock to the permanent adhesive, (f) applying a second tie coat to the second face of the sheet stock, and (g) applying a repositional adhesive to the second tie coat.
The label stock according to the present invention clearly indicates tampering since when the label stock is removed the tie coat comes with it but none of the other components, so that the indicia on the now exposed tie coat is visible. The label stock no longer has adhesive on the back because the tie coat transferred to the surface of the pressure sensitive adhesive when the label was removed from the surface to which it was applied. The security feature is now visible and the pressure sensitive adhesive is covered by the tie coat which causes the adhesive to lose its adhesive characteristics; therefore, the label cannot be reapplied to another surface.
It is the primary object of the present invention to provide a simple yet effective security label and method of manufacture thereof. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.